Antialiasing is a software technique for diminishing jaggies - stairstep-like lines that should be smooth. There are a lot of different assets in the Unity Store that provides this filter. I started from Amplify FXAA (Fast approXimate Anti-Aliasing) because it is free and is high rated. I was totally satisfied by the result for a long time.
I read about the CTAA (Cinematic Temporal Anti-Aliasing) from one article that compared differet antialiasing techniques. It is a preaty expensive asset, but it was on a 50% off sale so I decided to check it. It took some time to adjust the parameters, but the result exceeded my expectations. The smallest details are now distinguishable.
Indirect lighting (redflected lighting) is very important for getting a realistic image. But computation of correct indirect lighting is very time-consuming task even for a modern computer. Most of games pregenerate it and store in textures that are used futher for rendering. But the games, that generates locations proceduraly cannot precompute the lighting and shouls use other techniques. On of such technique is ambient occlusion. There are a lot of approaches for this techniques that differ in quality and performance. Compared several of them I stopped on Amplify Occlusion.
However, this filter produces small-scale shading and does not work well at the edge of the screen. Therefore, I also wrote my own ambient occlusion filter, which is focused on large-scale shading. Together with Amplify Occlusion, these filters significantly increase the quality of the picture, which is especially noticeable when the weather in game is cloudy and there is no light from the sun.